<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body>
    <form action="">
      <input type="text" required />
      <!-- 表单提示 -->
      <input type="text" placeholder="请输入" />
      <!-- 自动聚焦 -->
      <input type="text" autofocus />
      <!-- autocomplete，为了保护隐私尽量关闭 -->
      <input type="text" name="piggy" autocomplete="off" />
      <!-- multiple -->
      <input type="file" multiple />
      <button type="submit">submit</button>
    </form>
  </body>
</html>
